Conversion Products Research Articles

"…but I know something's not right here": Exploring the diagnosis and disclosure experiences of persons living with ALS.

Amyotrophic Lateral Sclerosis (ALS), an incurable motor neuron disease, primarily affects those between the ages of 60-79, and has an approximate post-diagnosis life-expectancy of only two to five years. The condition has an unpredictable but ultimately terminal trajectory that poses challenges for patients, caregivers and healthcare providers. While the diagnosis and disclosure are critical periods for intervention and support, knowledge regarding the relational, communicational and psychodynamic forces that occur within the process of diagnostic disclosure is relatively limited. The purpose of this study was to explore the experiences of persons living with ALS in the diagnosis and disclosure of the condition, with the support of their caregivers. We conducted a focus group and in-depth individual interviews with people living with ALS (n = 9), and caregivers (n = 9). The interviews were transcribed, cleaned, and anonymized, and then entered into NVivo 11 for thematic analysis. Participants discussed the diagnostic process, including inklings and subtle changes prior to diagnosis, attempts at self-diagnosis, and the lengthy assessment process. Time was also a consideration in the diagnostic disclosure process, in which participants shared how the disclosure was the product of longstanding conversations with their care providers. It was described as rarely a shock to finally have confirmation. Participants shared their information seeking strategies and needs for a diagnosis that, for them, typically came with insufficient information on the disease, prognosis, and next steps. This project serves as a step in bridging the relevant gaps in our knowledge and understanding towards improved person-centered care practices in the diagnosis and disclosure of ALS.

Response of Ceratophyllum demersum L. and its epiphytic biofilms to 6PPD and 6PPD-Q exposure: Based on metabolomics and microbial community analysis

The emerging contaminant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and its ozone conversion product N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q) pose a threat to aquatic ecosystems. Aquatic animals and plants exhibit vigorous responses at very low ambient concentrations. However, studies of submerged macrophytes, key producers in aquatic ecosystems, are limited and the full extent of their toxic effects and feedback mechanisms is unknown. To investigate the phytotoxicity of 6PPD and 6PPD-Q, we modeled plant responses to abiotic stress using Ceratophyllum demersum L. (C. demersum) as a representative submerged plant. Our findings indicate that 6PPD and 6PPD-Q disrupt physiological and biochemical processes in C. demersum, encompassing growth inhibition, reduction in photosynthetic pigments, induction of oxidative damage, and metabolic alterations. Moreover, unfavorable modifications to biofilms induced were also discernible supported by confocal laser scanning microscopy (CLSM) images and microbial community profiling. More importantly, we found a robust correlation between differentially expressed metabolites (DEMs) and dominant genera, and 6PPD and 6PPD-Q significantly altered their correlation. Overall, our results imply that even though C. demersum is a resilient submerged macrophyte, the toxic effects of 6PPD and 6PPD-Q cannot be disregarded.

The influence of pH on the liquid-phase transformation of phenolic compounds driven by nitrite photolysis: Implications for characteristics, products and cytotoxicity

The aqueous-phase conversion of phenolic compounds (PhCs) driven by nitrite photolysis has been recognized as a significant source of secondary brown carbon (BrC). However, the influence of pH on the conversion kinetics and product distribution of PhCs remains unclear. In this study, three representative PhCs with varying functional groups were selected to examine their aqueous-phase conversion kinetics in the presence of nitrite under different pH conditions and simulated sunlight conditions. The results indicate that as the pH increases, the decay rates of PhCs decrease, following first-order reaction kinetics. These varying decay rates also suggest that different substituents on the benzene ring significantly impact the reactivity of PhCs. The molecular composition of the products is pH-dependent, with 4-nitrocatechol (4NC) emerging as the primary reaction product. A range of conversion products were detected across different pH values: nitrification dominated at low pH, while hydroxylation products increased with rising pH, and polymerization products appeared prominently at high pH. Due to the electron-withdrawing effect of the nitro group on the benzene ring, fewer products formed from 4-nitrophenol were observed, and the visible absorption spectrum also showed a decreasing trend as the reaction progressed across various pH conditions. Toxicity assays on human non-small cell lung cancer cells (A549) revealed that the toxicity of the reaction products decreased with increasing pH. Correspondingly, the accumulation of reactive oxygen species (ROS) and apoptosis rates in cells also declined. This may be due to the fact that at lower pH levels, nitrophenols (NPs), which tend to promote ROS accumulation and cell death, dominate the product mix. This study provides valuable insights into the toxicological properties of secondary organic aerosols (SOA) formed from the photo-oxidation products of PhCs under different pH conditions. These findings contribute to a deeper understanding of the environmental and health impacts of SOA in atmospheric chemistry.

Optimizing trade-offs between light transmittance and intraspecific competition under varying crop layouts in a maize–soybean strip relay cropping system

Light is one of the most important environmental factors for plant growth and development. In relay cropping systems, crop layouts influence light distribution, affecting light use efficiency (LUE). However, the response of light interception, light conversion, and LUE for relay maize and relay soybean to different crop layouts remains unclear. We aimed to quantify the effect of crop layout on intraspecific and interspecific competition, light interception, light conversion, LUE, and land productivity between relay maize and relay soybean. We conducted a field experiment for four consecutive years from 2017 to 2020 in Sichuan province, China, comparing different crop layouts (bandwidth 2.0 m, row ratio 2:2; bandwidth 2.4 m, row ratio 2:3; bandwidth 2.8 m, row ratio 2:4), with sole maize and sole soybean as controls. The results showed that relay maize in the 2.0 m bandwidth layout had the largest leaf area index and plant biomass, the lowest intraspecific competitive intensity and the highest aggressiveness. Compared to a bandwidth of 2.0 m, a bandwidth of 2.8 m significantly decreased relay maize leaf area index by 11% and plant biomass by 24%, while a 2.4 m bandwidth caused roughly half these reductions. The 2.0 m bandwidth layout also significantly improved crop light interception and LUE compared to sole maize. The light interception, light interception rate, light conversion rate and LUE in relay maize all decreased significantly with increasing bandwidth, but they increased in relay soybean. The increased light transmittance to the lower and middle canopy with increasing bandwidth did not compensate for the loss of relay maize yield caused by increased intraspecific competition. However, it enhanced the yield of relay soybeans. Increasing the bandwidth by 80 cm increased the relay maize intraspecific competition by 580%, and reduced maize yield by 33%, light interception by 12%, and LUE by 18%. In contrast, the relay soybean intraspecific competition was reduced by 64%, and the soybean yield was increased by 26%, light interception by 32% and LUE by 46%. Relay cropping systems with a 2.0 m bandwidth optimize the trade-off between light transmittance and intraspecific competition of relay crops. These systems achieve the highest LUE, group yield and economic benefits, making them a recommended crop layout for the southwest regions of China. Our study offers valuable insights for developing strip relay cropping systems that maximize light utilization and contributes to the theoretical understanding of efficient sunlight use in relay cropping practices.

An emerging route for efficient conversion of monopotassium phosphate via a pilot-scale electrodialysis metathesis

This study explores energy-efficient KH₂PO₄ (KDP) preparation, examining its implications for sustainability, and offers insights on enhancement and benefits. For the first time, electrodialysis metathesis (EDM) process was considered as a potential technique for efficient conversion and cleaner production of KDP in this study. The effects of key operational parameters including applied voltage, initial feed concentration, concentration ratio, and volume ratio on the conversion performance of EDM were systematically investigated. The promising conditions were established with an applied voltage of 2.3 V per repeating unit, a concentration ratio of 0.5 M NH4Cl to 0.6 M KCl, and a critical 1.43-fold volume ratio, yielding a high-purity KDP solution of 96.65 % at 78.52 g/L with an energy consumption rate of 0.52 KWh/kg. An economic evaluation indicates a 15.4 % cost reduction compared to the market price, presenting the EDM process as a viable and leading technology for the production of high-purity KDP.

Process simulation and economic evaluation of the industrial production of triacetin from glycerol: Comparing acetic acid and acetic anhydride as possible reagents

The objective of this work was to simulate, in Aspen HYSYS® v12.1, the process of obtaining triacetin from glycerol through three chemical routes: via acetic acid (Route 1), acetic anhydride (Route 2), and a combination of acetic acid and acetic anhydride in two separate reactors (Route 3). Additionally and as a novelty, it was investigated the technical and economic viability of a multipurpose plant to this end. It was verified that Route 1 resulted in the best triacetin breakeven prices, even though it would still not be competitive in the considered economic context. On the other hand, Route 2 presented the worst performance due to low conversion (11 %) and higher price of acetic anhydride. The combined route resulted in intermediate breakeven prices for triacetin, despite achieving the highest conversion (79 %) and highest final product purity (96 %). Yield/selectivity and the separation steps were identified as the main bottlenecks in these processes, with reactors and distillation columns accounting for more than 95 % of the equipment costs. The multipurpose plant proved technically possible, and it can be economically interesting depending on the market prices for acetic acid and acetic anhydride.

Highly stable Co@BC catalysts encapsulated in biochar for efficient lignin hydrogenolysis to valuable monophenols

The development and utilization of renewable lignin from industrial crops to produce high-value bio-based chemicals and fuels is of great significance in reducing dependence on fossil resources and promoting green chemistry. However, conventional metal-supported catalysts often suffer from poor metal dispersion and particle agglomeration during lignin conversion, resulting in insufficient catalytic activity. To address these challenges, a novel biochar-encapsulated cobalt catalyst (Co@BC) was developed in this study for efficient lignin hydrogenolysis. The catalyst formed a unique thin carbon layer structure by encapsulating cobalt nanoparticles in biochar, which enhanced metal dispersion and prevented particle agglomeration. The performance of the catalysts was systematically evaluated at different calcination temperatures. Co@BC-650 showed the best results with a lignin liquefaction degree of 79.7 % and a monophenol yield of 19.1 wt%. This yield was significantly higher than that of the supported Co/BC-650 catalyst, which only reached 15.4 wt%. The thin carbon layer not only facilitated the reduction of cobalt species at 650 °C, but also provided antioxidant protection and maintained the stability of metallic cobalt, which was essential for H2 adsorption and activation. In addition, Co@BC-650 exhibited excellent stability with little loss of activity after 3 cycles. This study provides an efficient and sustainable method for the selective production of monophenols from renewable lignin from industrial crops, which has the potential to be widely applied for biomass conversion and large-scale sustainable chemical production.

Triple Enzymatic Cascade Reaction to Produce Hydroxytyrosol Acetate from Olive Leaves Using Integrated Membrane Bioreactors.

An integrated system of three membrane bioreactors (MBRs) has been developed that cascades three different enzymatic reactions. The integrated system was applied to produce hydroxytyrosol acetate from oleuropein extracted from olive leaves. Different reactor configurations for each reaction were tested and individually optimized to select the MBR to ensure high conversion and continuous production of oleuropein aglycone (OA), hydroxytyrosol (HY) and hydroxytyrosol acetate (HA). Based on this study, the most performing configuration of the integrated system was identified. In the first reaction, oleuropein was converted to OA using a biocatalytic membrane reactor (BMR) with immobilized β-glucosidase in polymeric membranes (conversion 95 %). The OA was then fed to another BMR, where it was converted to HY (conversion: 70 %) by an immobilized mutant of the promiscuous hydrolase/acyltransferase (PestE) (from the thermophilic archaeon Pyrobaculum calidifontis VA1). The HY produced was then acetylated using PestE immobilized on magnetic nanoparticles in a multiphase MBR (conversion: 98 %) and simultaneously extracted (extraction: 98 %) in ethyl acetate. The work demonstrates that continuous cascade enzymatic reactions can be engineered using artificial membranes to tailor enzyme compartmentalization, mass transport and phase contact according to reaction requirements. Besides, environmental factors proved the sustainability of the integrated membrane bioreactive system.

Mixed atomic-scale electronic configuration as a strategy to avoid cocatalyst utilization in photocatalysis by high-entropy oxides

To enhance the activity of photocatalysts for hydrogen production and CO2 conversion, noble metal cocatalysts as electron traps and/or acceptors such as platinum or gold are usually utilized. This study hypothesizes that mixing elements with heterogeneous electronic configurations and diverse electronegativities can provide both acceptor and donor sites of electrons to avoid using cocatalysts. This hypothesis was examined in high-entropy oxides (HEOs), which show high flexibility for atomic-scale compositional changes by keeping their single- or dual-phase structure. A new high-entropy oxide was designed and synthesized by mixing elements with an empty d orbital (titanium, zirconium, niobium and tantalum) and a fully occupied d orbital (gallium). The oxide, synthesized by high-pressure torsion followed by calcination, had two phases (88 wt% orthorhombic (Pbcn) and 12 wt% monoclinic (I2/m)) with an overall composition of TiZrNbTaGaO10.5. It exhibited UV and visible light absorbance with a low bandgap of 2.5 eV, low radiative electron-hole recombination and oxygen vacancy generation due to mixed valences of cations. It successfully acted as a photocatalyst for CO and CH4 production from CO2 conversion and hydrogen production from water splitting without cocatalyst addition. These findings confirm that introducing heterogeneous electronic configurations and electronegativities can be considered as a design criterion to avoid the need to use cocatalysts.

Investigations of Mechanisms Leading to Capacity Differences in Li/Na/K-Ion Batteries with Conversion-Type Transition-Metal Sulfides Anodes.

Conversion-type transition-metal sulfides (CT-TMSs) have been extensively studied as the anode of Li/Na/K-ion batteries due to their high theoretical capacity. An issue with the use of the material in the battery is that a large capacity difference is commonly observed. However, the underlying mechanism leading to the problem is still unknown. Here, the large capacity difference mechanisms of CT-TMSs anodes in the Li/Na/K-ion storage are elucidated, which arises from the difference in conversion degree and size of conversion products. Specifically, the increase in ionic radius will cause the increase in insertion-reaction ion diffuse energy barrier and conversion-reaction Gibbs free energies of phase transformation to decrease reaction kinetics, which causes a decrease in conversion degree and an increase in size of conversion products, thus leading to reduction in capacity. The increase in size and the decrease in the amount of conversion products inevitably reduce the amount of spin-polarized electrons injection into Fe and corresponding ions storage amount into sulfides during the ion-electron decoupling storage, thus reducing the capacity. The research clarifies the capacity difference mechanisms of CT-TMSs anodes in Li/Na/K storage, providing valuable insights for designing Li/Na/K storage high-capacity anodes.

Boosting bio-lipids hydrodeoxygenation via highly dispersed and coking-resistance bimetallic Ni-La/SiO2 catalyst

A highly dispersed and coking-resistance bimetallic Ni-La/SiO2 catalyst was prepared for the selective hydrodeoxygenation (HDO) of fatty acid methyl esters (FAMEs) and non-edible bio-lipids to hydrocarbon compounds. Under optimum conditions, full conversion of methyl palmitate (MP) and 97.6% selectivity for pentadecane (PD) were achieved. The catalyst also exhibited high conversion and excellent desired product selectivity for the HDO of various model FAMEs, fatty acids, trilaurin, jatropha oil (JO) and waste cooking oil (WCO). Multiple characterizations show that the embedding effect (metal−support or metal−metal interaction) associated with the introduction of metallic La not only contributes to the formation of well-dispersed Ni particles and abundant active Niδ+−OV−LaOx species, but also prevents the migration and sintering of metallic Ni particles at high temperatures. Furthermore, the mutual transformation of the La2O3 and La2O2CO3 crystal phases effectively inhibits coke deposition on the catalyst surface during the reaction process, resulting in remarkable stability and reusability of the catalyst. A plausible reaction network and mechanism for the catalytic HDO of MP over Ni-La/SiO2 catalyst were proposed. This method of constructing a catalytic system can provide a basis for the development of efficient catalysts for the HDO of non-edible bio-lipids.

Model-based optimization strategies for direct hydrogenation of carbon dioxide to dimethyl ether

This study discusses model-based optimization strategies for CO2 hydrogenation to dimethyl ether (DME) over a CuZnZr (CZZ) and ferrite (FER) mixed catalyst system in a packed-bed reactor configuration. A two-dimensional axisymmetric, nonisothermal packed-bed reactor model was developed using COMSOL Multiphysics 6.2 software. The model solves two-dimensional (radial and axial) heat and mass transport equations in the packed-bed and integrates intraparticle diffusion and heat transfer in a 1D approach. This powerful feature differs from a traditional porous media approach and takes into account any heat and mass transfer limitations that may exist. Analysis shows that the heat transfer limitations are negligible, but strong internal mass transfer limitations were observed at 10 ≤ WHSV ≤ 90 h−1 on the FER catalyst and at 240 °C. The optimum catalyst composition (i.e., mixing ratio) varies depending on the operating regime. The FER catalyst weight in the mixture can be as low as 5 wt.%, but the ideal composition depends on the internal mass transfer limitation and its relationship with the operating regime (i.e., weight hourly space velocity, temperature). A catalyst composition of 80 wt.% CZZ and 20 wt.% FER was suggested; this composition can provide high CO2 conversion and DME production rates at a wide range of temperatures and flow rates.

Protective effect of ginseng berry saponin conversion products on skin photodamage caused by UVB in vitro and in vivo

Ultraviolet (UV) B irradiation is closely related to skin aging and skin damage. Here, we report the photoprotective mechanism of action of ginseng berry rare saponins (GFRS) on UVB-induced damage to human keratinocytes and mouse skin. Several UVB irradiation–induced cytotoxicity and oxidative stress responses were assessed. GFRS preconditioning significantly improved HaCaT cell survival and reduced the levels of the DNA damage markers histone H2AX and cyclobutane pyrimidine dimer. Under oxidative stress, GFRS could reduce the transformation and loss of the mitochondrial membrane potential to the monomer form; effectively clear the expression of lipid reactive oxygen species, malondialdehyde, and other peroxides, and restore total superoxide dismutase, glutathione peroxidase, and catalase levels. The occurrence of ferroptosis after UVB induction was also studied. Erastin exacerbated the induced cellular iron overload, whereas GFRS and Fer-1 reversed this response to varying degrees. Mechanistically, GFRS activated the Nrf2/HO-1/GPX4 pathway and inhibited the phenomenon of ferroptosis in cells. Our findings were confirmed using a mouse model of UV induced skin injury. GFRS not only mitigated lipid peroxides and iron overload in tissues but also prevented skin barrier damage and collagen loss. Therefore, GFRS shows potential as a novel functional product as it protects the skin from UVB light–induced damage.

Progress in carbon capture and impurities removal for high purity hydrogen production from biomass thermochemical conversion

Renewable hydrogen production from biomass thermochemical conversion is an emerging technology to reduce fossil fuel consumptions and carbon emissions. Biomass-derived hydrogen can be produced by pyrolysis, gasification, alkaline thermal treatment, etc. However, the removal of impurities from biomass thermochemical conversion products to improve hydrogen purity is currently technical bottleneck. It is important to assess and investigate the types and properties of impurities, the difficulty of separation, and the impact on downstream utilization of hydrogen in the biomass-derived hydrogen production process. The key objectives of this comprehensive review are: (1) to reveal the current status and necessity of developing biomass-derived hydrogen production; (2) to evaluate the types, devices and impurities distribution of biomass thermochemical conversion; (3) to explore the formation pathways and removal technologies of typical impurities of tar, CO2, sulfides, and nitrides in hydrogen production process; and (4) to propose future insights on the separation technologies of typical impurities to promote the gradual substitution of biomass-derived hydrogen for fossil-derived energy.

C/N conversion and pigment production of Blastochloris sulfoviridis characterized by bacteriochlorophyll b under near-infrared single-wavelength laser

High carbon use efficiency (CUE) of photosynthetic bacteria (PSB) can concurrently increase biomass and reduce CO2 emissions. In the PSB study, light-oxygen conditions are crucial factors influencing the growth of these bacteria. Bacteriochlorophyll (BChl) b (absorption spectra: 970–1040 nm), due to its unique absorption spectrum, can be considered a crucial complement to BChl a (absorption spectra: 780–890 nm). We investigate the effects of four light-oxygen conditions on biomass, C/N conversion, and pigment production using five individual light sources in Blastochloris sulfoviridis (B. sulfoviridis), producing BChl b, isolated using 940±10 nm laser unexpectedly. Biomass, CUE, and pigment production follow the order under different light-oxygen conditions: light-anaerobic > light-aerobic > dark-aerobic > dark-anaerobic. The maximum biomass (1386.88 mg/L), highest CUE (0.95 g-biomass/g-CODremoved and 0.49 g-biomass carbon/g-CODremoved), and highest pigment production are observed under full spectrum (40 W)-anaerobic, 940-anaerobic, and 850-anaerobic conditions, respectively. Compared to light-aerobic, the nitrogen-fixing ability of B. sulfoviridis is enhanced under light-anaerobic conditions. This study contributes to research on resource recovery and greenhouse gas emissions reduction in PSB wastewater treatment.

Investigating Pt/Pumice catalyst for efficient 3-methyl-1-butanol conversion

The objective of this study was to obtain a modified Pt/pumice catalyst to support the conversion reaction of 3-methyl-1-butanol under specific reaction conditions. To achieve this objective, the first step involved preparing modified pumice catalyst pellets by impregnating them with Pt metal followed by activation at a temperature of 500 °C. The second step involved characterizing the Pt/pumice catalyst, including the surface distribution of Pt metal using SEM. The third step involved conducting the catalyst activity test against 3-methyl-1-butanol in a reactor (furnace) at temperatures ranging from 400 to 500°C with a flow system for the feed. The fourth step involved analyzing the conversion results using GC-MS chromatograms. The research results showed that the Si/Al ratio in the modified Pt/Pumice catalyst using a PtCl4 solution with a concentration of 0.0321 M for impregnation was 4:1, compared to 4.8:1 for Pt/Zeolite and 3.2:1 for Pt/ABP. The modified catalyst activity test for 3-methyl-1-butanol showed the following conversion results: Pt/Pumice 27.63%, Pt/Zeolite 23.85%, Pt/Black Pumice 14.81%, and for platinum catalyst, the conversion was 22.35%. These results indicated that the highest conversion was observed in the treated sample A-3 under the reaction condition of 450°C. The conversion products analyzed using GC-MS showed the presence of three molecules: 3-methylbutanal, 2-methylbutanal, and anhydrous isobutanoate.

Biomass Demineralization and Pretreatment Strategies to Reduce Inhibitor Concentrations in Itaconic Acid Fermentation by Aspergillus terreus

Itaconic acid (IA) is a platform chemical, derived from non-petroleum sources, produced through the fermentation of glucose by Aspergillus terreus. However, producing IA from alternative sugar sources (e.g., lignocellulose) has been shown to be problematic, requiring post-hydrolysis mitigation to allow growth and IA production by the fungus. It is well known that the side products of lignocellulosic biomass conversion to sugars act as microbial growth inhibitors. An uncommon feature of fungal organic acid fermentations is production inhibition caused by mineral ions in biomass hydrolysate after pretreatment and enzymatic hydrolysis. To minimize mineral introduction during pretreatment and hydrolysis, we determined the sources of growth and production inhibitors at each of these steps. Biomass demineralization and four pretreatment strategies were evaluated for inhibitor introduction. Dilution assays determined the approximate degree of inhibition for each hydrolysate. An ammonium hydroxide pretreatment of demineralized wheat straw presented the lowest concentration of inhibitors and concomitant lowest inhibition: subsequent fermentations produced 35 g L−1 IA from wheat straw hydrolysate (91 g L−1 sugar) without post-hydrolysis mitigation.

Niobium Pentoxide as an Acid Catalyst: An Overview

The global chemical industry is under increasing pressure to adopt more sustainable practices, as most chemical products exceed environmental safety limits. Given that chemical production largely relies on catalytic processes, the development of solid acid catalysts has become crucial for more sustainable production. Among these catalysts, niobium pentoxide stands out due to its strong acid sites, which remain active in the presence of water, and its stability under hydrothermal conditions. Recent studies have demonstrated that these solids maintain their catalytic activity even in the presence of strong bases, making them unique catalysts. This review explores the potential of niobium pentoxide as an acid catalyst, addressing advances in synthesis techniques, surface modifications, and combinations with other materials to enhance its catalytic performance in sustainable applications, such as biomass conversion and biofuel production, opening new pathways for the production of greener chemicals. Finally, the future perspectives of niobium pentoxide - based catalysts in green chemistry are discussed.

Enhancing methane production from distillers’ grains by cattle manure in solid-state anaerobic digestion: Focusing on biodegradability, acidification and indigenous microorganisms

Distillers’ grains has high potential in methane production but the process is affected by the acidification in anaerobic digestion. To enhance the methane production in solid-state anaerobic digestion, distillers’ grains was co-digested with cattle manure in different proportions in this study. Compared to distillers’ grains, cattle manure performed lower biodegradability but higher alkalinity and nutrients, hence relieved acidification and drove microbial succession for methane enhancement in the co-digestion with distillers’ grains. The highest increase in total methane yield (10.67 %) was observed in the co-digestion of distillers’ grains and cattle manure at the proportion of 70:30 (T3). This was the synergistic action of reduced acidification, relatively high biodegradability of feedstocks, and balanced composition of hydrolytic bacteria, syntrophic bacteria and acetoclastic methanogens. Further analysis revealed the positive effects of indigenous microorganisms derived from distillers’ grains and cattle manure in methane enhancement. The enrichment of Sedimentibacter, Desulfitibacter, Tepidanaerobacter from distiller's grains, and Eubacterium, Methanoculleus, Methanobacterium, Methanobrevibacter mainly from cattle manure synergistically promoted organics conversion and methane production in T3. This study further affirmed the potential use of distillers’ grains in solid-state anaerobic digestion and provided a favorable strategy for its better methane production.

Research on reaction mechanisms on chemical looping gasification of naphthalene over NiFe2O4 for syngas production: An experimental and theoretical study

The effective removal of tar during biomass gasification is a significant challenge that can be addressed by chemical looping gasification (CLG), which offers a promising alternative for converting biomass into syngas with reduced tar generation. In this study, we investigated the mechanism of CLG of naphthalene as a model biomass tar compound over NiFe2O4 to produce syngas. Both experimental and simulation results indicate the optimal operating conditions for syngas production are 1000℃ and an O/C ratio of 1:1. Under the optimal reaction conditions, the experimental and simulated CO yields were 67 vol% and 73 vol%, respectively, while H2 yields were 22 vol% and 24 vol%. Additionally, carbon conversion rates reached 78% and 76%. Thermodynamic calculations and molecular dynamics simulations revealed that the reactions proceed spontaneously, with increasing temperature favoring naphthalene conversion and syngas production. Density functional theory results indicate that the reaction pathway centered on the carbon at the α-position is the key to naphthalene and NiFe2O4 conversion. The optimal reaction pathways for H2 and CO formation were explored. This study on the CLG of naphthalene over NiFe2O4 provides a theoretical basis for the development of more efficient CLG processes with reduced tar formation.